fix: allow optional and union types to be marks as "stdlib"

Fixes and issue where nested simple types were spuriously marked as cyclic.

Author: seandstewart

src/typelib/graph.py

@@ -142,7 +142,7 @@ def get_type_graph(t: type) -> graphlib.TopologicalSorter[TypeNode]:
                 qualname = inspection.qualname(child)
                 *rest, refname = qualname.split(".", maxsplit=1)
                 is_argument = var is not None
-                module = getattr(child, "__module__", None)
+                module = ".".join(rest) or getattr(child, "__module__", None)
                 if module in (None, "__main__") and rest:
                     module = rest[0]
                 is_class = inspect.isclass(child)

src/typelib/py/inspection.py

@@ -480,6 +480,13 @@ def isbuiltintype(
 
 @compat.cache
 def isstdlibtype(obj: type) -> compat.TypeIs[type[STDLibtypeT]]:
+    if isoptionaltype(obj):
+        nargs = tp.get_args(obj)[:-1]
+        return all(isstdlibtype(a) for a in nargs)
+    if isuniontype(obj):
+        args = tp.get_args(obj)
+        return all(isstdlibtype(a) for a in args)
+
     return (
         resolve_supertype(obj) in STDLIB_TYPES
         or resolve_supertype(type(obj)) in STDLIB_TYPES

tests/models.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import dataclasses
+import datetime
 import enum
 import typing
 
@@ -54,3 +55,10 @@ class TDict(typing.TypedDict):
 
 class GivenEnum(enum.Enum):
     one = "one"
+
+
+@dataclasses.dataclass
+class UnionSTDLib:
+    timestamp: datetime.datetime | None = None
+    date_time: datetime.datetime | None = None
+    intstr: int | str = 0

tests/unit/unmarshals/test_api.py

@@ -142,6 +142,13 @@
         given_input="one",
         expected_output=models.GivenEnum.one,
     ),
+    union_std_lib=dict(
+        given_type=models.UnionSTDLib,
+        given_input={"timestamp": 0},
+        expected_output=models.UnionSTDLib(
+            timestamp=datetime.datetime.fromtimestamp(0, datetime.timezone.utc)
+        ),
+    ),
 )
 def test_unmarshal(given_type, given_input, expected_output):
     # When